The invention relates to a method and system for controlling operation of a system based on exhaust system temperature measured downstream of an exhaust gas cooler.
Some internal combustion engines are designed to be used in hazardous or potentially hazardous environments, such as underground mining applications and offshore drilling applications. Typically, such engines are mechanically controlled. More specifically, fuel injections are controlled based on movement of a cam shaft. Furthermore, fuel injection timing for such engines is a function of engine load, and not engine speed. As a result, these engines are inefficient.
For non-hazardous environments, engines are typically controlled by an electronic control unit having volatile and non-volatile memory, input and output driver circuitry, and a processor capable of executing a stored instruction set. A particular electronic control unit communicates with numerous sensors, actuators, and other control units to control various functions of the engine and its associated systems. Such an electronic control unit, however, is not configured to be used in hazardous or potentially hazardous environments, and does not include a means for effectively controlling engine temperatures and associated component temperatures.
The invention addresses the shortcomings of the prior art by providing an improved method and system for controlling engine operation, wherein the method and system are especially useful in hazardous or potentially hazardous environments. The method and system of the invention provide significantly improved engine efficiency compared with prior art systems and methods that include mechanically controlled engines.
Under the invention, a method is provided for controlling an engine of a system having an exhaust system connected to the engine, and the exhaust system includes an exhaust gas cooler. The method includes sensing exhaust system temperature downstream of the exhaust gas cooler; comparing the exhaust system temperature to a temperature threshold that is less than 200 degrees Celsius; and adjusting an engine control parameter when the exhaust system temperature exceeds the temperature threshold.
Advantageously, operating temperatures of the system may be effectively controlled by the method of the invention so as to allow the system to operate in hazardous and potentially hazardous environments. Furthermore, the method allows the engine to continue operation when the temperature threshold is exceeded. Thus, an operator is provided time to respond to a situation, rather than having the engine abruptly shut down.
Sensing exhaust system temperature may include sensing temperature of exhaust gases. Alternatively or supplementally, sensing exhaust system temperature may include sensing temperature of exhaust system piping.
Adjusting an engine control parameter preferably includes reducing available engine torque. As a result, fuel supplied to the engine is reduced, but the engine may continue to operate. Other examples of adjusting an engine control parameter include adjusting timing of a fuel injection to the engine, adjusting air supplied to the engine, adjusting exhaust gas re-circulation rate, and reducing engine loading.
The method may also include comparing the exhaust system temperature to an additional temperature threshold, and shutting down the engine when the exhaust system temperature exceeds the additional temperature threshold.
Further under the invention, a system for controlling engine operation includes an exhaust system temperature sensor for sensing exhaust system temperature downstream of an exhaust gas cooler, and a controller in communication with the exhaust system temperature sensor. The controller including control logic for comparing the exhaust system temperature to a temperature threshold that is less than 200 degrees Celsius, and control logic for adjusting an engine control parameter when the exhaust system temperature exceeds the temperature threshold.
A computer readable storage medium according to the invention is also provided. The computer readable storage medium has information stored thereon representing instructions executable by an engine controller that is in communication with an engine and an exhaust system temperature sensor disposed downstream of an exhaust gas cooler. The computer readable storage medium includes instructions for determining exhaust system temperature downstream of the exhaust gas cooler based on signals provided by the exhaust system sensor; instructions for comparing the exhaust system temperature to a temperature threshold that is less than 200 degrees Celsius; and instructions for adjusting an engine control parameter when the exhaust system temperature exceeds the temperature threshold.
These and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.